A210 ADLERCREUTZIA IS DEPLETED IN UC PATIENTS, EVEN BEFORE CLINICAL DIAGNOSIS, AND INVERSELY CORRELATES WITH FECAL ELASTOLYTIC ACTIVITY

Background

A combination of genetics, environmental, and immune factors contribute to the development of ulcerative colitis (UC). Host proteolytic imbalance has been reported in active UC. Preliminary results from our lab suggest microbial proteolytic activity is increased before as well as after onset of UC, and transfer of this activity to mice contributes to inflammation.

Aims

Our aim was to correlate the elastolytic activity of fecal samples from individuals at risk for IBD, before and after onset of ulcerative colitis, with their fecal microbiota profiles

Methods

We first investigated proteolytic activity in fecal samples from individuals at risk to develop UC (pre-UC, n=12) prior to disease onset and after UC diagnosis (post-UC, n=7) and matched healthy controls (n=66). Microbial community analysis was performed by sequencing the V4 region of the 16S rRNA gene region using Illumina MiSeq platform. Sequences were analyzed with QIIMEv1.9.0. We measured bacterial proteolytic activity, using a FITC-elastin assay.

Results

Microbial community analysis revealed that the overall diversity (both richness and evenness) in UC patients was decreased compared to healthy controls as well as pre-UC patients. The relative abundance of the genus Adlercreutzia was decreased by 3.1 fold in pre-UC patients compared to healthy controls and was further decreased in post-UC (3.8 fold). The presence of Adlercreutzia was also found to be negatively correlated (r=-0.47, p<0.0001) with elastolytic activity in stool supernatant, suggesting a possible protective role in the disease.

Conclusions

We found novel potentially protective bacteria, Adlercreutzia, which was depleted in UC patients, even before clinical diagnosis and correlated negatively with proinflammatory elastolytic activity described previously in IBD. The protective mechanisms are under investigation.

On behalf of the CCC-GEM Project consortiumand Supported by a CCC GIA to EFV

Funding Agencies

CCC

A48 COLITIS FAVORS THE EXPANSION OF BACTERIA THAT ACTIVATE PAR2 AMPLIFYING INFLAMMATORY RESPONSE

Background

Proteolytic imbalance has been described in patients with inflammatory bowel disease (IBD) and in different models of experimental colitis. Although the proteases reported to be increased are mainly from the host, the role of bacterial proteases has recently emerged, as they can promote inflammation, in part, through activation of Protease-activated receptors (PARs). PAR2 deficient mice are resistant to inflammation and PAR2 activation affects multiple aspects of the tissue response to injury. However, PAR2 communicates with other receptors such as toll-like and other PARs, which are important in multiple immune signaling pathways. Thus, the direct implication of PAR2 in colitis, and specifically the activation of the external domain by microbial proteases, remains unclear.

Aims

To study the role of PAR2 and bacterial proteases in experimental colitis.

Methods

C57BL/6 and protease-resistant PAR2 (R38E-PAR2) mice, in which activation site of PAR2 is missing, were given 3.5% dextran sodium sulfate (DSS) in drinking water for 5 days followed by 2 days of water. Control C57BL/6 (wild-type) and R38E-PAR2 mice received only water. Percent weight change was evaluated along the study. Fecal microbiota (16S Ilumina), expression of proinflammatory genes (Nanostring), gut permeability (Ussing chamber), proteolytic activities (colorimetric assay) and bacterial translocation (plating) were measured in all mice at sacrifice. Inflammation was determined by analyzing stool consistency, fecal blood and by microscopic scores (Cooper score). Bacteria with proteolytic activity were isolated using agar-media with protein as main nutrient and bacterial capacity to release the external domain of PAR2 was tested in cells harbouring luciferase at the PAR2 N terminus.

Results

Wild-type, but not R38E-PAR2 mice, had increased expression of several pro-inflammatory genes, such as tnf, map3k and tlr, gut dysfunction and increased intestinal permeability, increased bacterial translocation into spleen and altered microbiota profiles following DSS treatment. DSS induced colitis in both mouse strains, but clinical and microscopic scores were significantly lower in R38E-PAR2 compared with wild-type mice. DSS increased the abundance of opportunistic pathogens such as Enterococcus and Staphylococcus only in wild-type mice. Proteolytic phenotype of these bacteria, and their capacity to cleave the external domain of PAR2, was confirmed.

Conclusions

Mice lacking the activation site of PAR2 are protected from DSS-induced colitis. DSS treatment leads to expansion of bacteria releasing active proteases, which may mediate injury through PAR2. These results suggest that intestinal injury promotes microbial proteolytic imbalance which in turn, exacerbates inflammation.

Funding Agencies

CAG, CCC, CIHR

A55 LACK OF EXPERIMENTAL REPRODUCIBILITY IN PRECLINICAL RESEARCH IS INFLUENCED BY THE NUTRITIONAL PROFILE OF STANDARD RODENT CHOWS

Background

Lack of experimental reproducibility, particularly in studies investigating the microbiota, is of growing concern to the scientific community. Factors such as environment, stress, and sex have been identified as contributors, whereas dietary composition has received less attention.

Aims

To profile the use of standard rodent chows in research institutions, analyze the nutrient content of common rodent chows, and assess the impact of different chows on microbiota profiles.

Methods

A survey was conducted to evaluate which rodent chows are used by research institutions worldwide. Seven standard rodent chows were selected for analysis of ingredients, fermentable carbohydrate (FODMAP) and gluten content. FODMAP content was measured by high-performance liquid-chromatography and enzymatic assays, and gluten content was assessed by a commercial kit using G12 antibody. Forty C57BL/6 mice were randomized to 4 groups of 10 mice (5 male, 5 female). Group A was euthanized at baseline. Group B received the breeding institution chow (LabDiet 5066). Group C received ResearchDiets AIN93G (low FODMAP and gluten content). Group D received LabDiet 5001 (high FODMAP and gluten content). After 3 weeks, cecal contents were collected and analyzed by 16S rRNA gene sequencing; short- and branched-chain fatty acids (SCFA, BCFAs) content was also determined.

Results

Twenty-eight different types of rodent chows were reported to be used by 45 international survey respondents. Ingredient composition of the standard chows varied widely, resulting in differences in FODMAP and gluten content. Microbiota analysis of cecal contents revealed that gut microbiota composition was altered by the standard chows, as reflected by significantly different clusters in β-diversity analysis as well as by altered α-diversity. Microbiota diversity was also influenced by sex in Groups A and B (p<0.01). Total SCFA levels were lower (p=0.03) and BCFA levels were higher (p=0.01) in Group C compared to Group B.

Conclusions

Our results suggest that the composition of the diet not only significantly impacts gut microbiota profiles and fermentation patterns but may also emphasize sex differences in preclinical studies, with major implications for the reproducibility of results across laboratories.

Funding Agencies

CIHRThe Canadian Nutrition Society

A35 MICROBIAL PROTEOLYTIC SIGNATURE IN ULCERATIVE COLITIS INDUCES AN INFLAMMATORY SIGNATURE IN MICROBIOTA-HUMANIZED MICE

Background

Altered gut microbiota composition has been associated with inflammatory bowel diseases (IBD) including ulcerative colitis (UC), but causality and bacterially-driven mechanisms, are unclear. Proteases within the gastrointestinal tract play a critical role in maintaining homeostasis and are tightly regulated by anti-proteases. Host-derived proteolytic imbalances have been described in IBD, including UC, however, the role of intestinal microbiota as a source of proteases and anti-proteases has largely been ignored.

Aims

To study microbial proteolytic activity and intestinal microbiota profiles in a cohort of individuals at-risk for IBD, and in those individuals that develop UC at follow-up.

Methods

Fecal samples were collected from healthy individuals at-risk for IBD and who went on to develop UC (pre-UC; n=14) and again after UC diagnosis (post-UC, n=10). Fecal samples from matched at-risk individuals that did not develop UC were used as healthy controls (n=52). Overall fecal proteolytic and elastolytic activity was measured. We performed metagenomics sequencing in 4 UC subjects (pre and post) and 4 matched HC using Illumina Hi-Seq from stool DNA. To investigate bacterial origin and functional significance, pregnant germ-free (GF) mice were colonized with a fecal sample from a selected UC subject (pre and post) and a matched HC. Naturally colonized litters were followed for 12 weeks, after which proteolytic activities and signs of inflammation were measured.

Results

Fecal proteolytic and elastase activity was increased in pre- and post-UC samples compared to HCs. Metagenomics revealed over 20k genes were significantly different between HC and pre-UC samples, and of these, 440 related to proteases and peptidases. Increased fecal proteolytic activity, higher lipocalin levels, and increased colonic polymorphonuclear cells in colonic H&E sections was observed in pre- and post-UC colonized mice compared to HC colonized mice. Mice colonized with pre-UC microbiota showed increased mRNA expression of genes linked to immunological disease, antimicrobial and inflammatory responses (ie. Tlr2, Tlr5, Nod2, and Il1b) as compared to HC colonized mice.

Conclusions

These results suggest increased fecal proteolytic activity is observed prior to the onset and clinical diagnosis of UC in patients at-risk for IBD, and upon transfer to mice born from colonized GF dams, low-grade inflammation develops. These pathways could be developed as novel non-invasive biomarkers to monitor at-risk populations. Submitted on behalf of the CCC-GEM Project consortium. Supported by CCC GIA to EF Verdu

Funding Agencies

CCC

Randomized trials of alcohol-use interventions with college students and their parents: lessons from the Transitions Project

BACKGROUND

Matriculation from high school to college is typified by an increase in alcohol use and related harm for many students. Therefore, this transition period is an ideal time for preventive interventions to target alcohol use and related problems.

PURPOSE

The purpose of this report is to describe the design and methods used in the Transitions Project, a randomized controlled trial of two interventions designed to prevent and reduce heavy episodic drinking and alcohol-related negative consequences among incoming college students.

METHODS

This study used a 2 × 2 factorial design to investigate the effects of a two-session brief motivational intervention delivered to students and a handbook-based parent intervention. Interventions were administered to students and parents. Follow-up assessment took place at 10- and 22-months post-baseline.

RESULTS

The Transitions Project successfully recruited and retained participants across a major transition period (i.e., entering college), administered and compared two distinct but complementary interventions, and collected and analyzed highly skewed data. The application of a factorial design and two-part latent growth curve modeling allowed us to examine main and interactive intervention effects in terms of both initiation and growth in heavy drinking and alcohol-related problems.

LIMITATIONS

While we conducted successful tests of our primary and secondary study hypotheses over a lengthy follow-up period, our study design did not permit full interpretation of null findings. We suggest that researchers carefully consider assessment timing, tests of assessment reactivity, and ensure objective tests of intervention efficacy when conducting clinical trials of motivational interventions.

CONCLUSIONS

The lessons we learned while conducting this trial have the potential to assist other researchers designing and conducting future preventive interventions targeting parents and college students. The data analytic procedures presented can also help guide trials that plan to analyze zero-inflated non-normal outcome data.

Temporal relation of cardiac hypertrophy, oxidative stress, and fatty acid metabolism in spontaneously hypertensive rat

Left ventricular hypertrophy is an adaptive response to hypertension, and an independent clinical risk factor for cardiac failure, sudden death, and myocardial infarction. As regression of cardiac hypertrophy is associated with a lower likelihood of cardiovascular events, it is recognized as a target of antihypertensive therapy. This necessitates identification of factors associated with the initiation and progression of hypertrophy. Oxidative stress and metabolic shift are intimately linked with myocardial hypertrophy, but their interrelationship is not clearly understood. This study proposes to identify the temporal sequence of events so as to distinguish whether oxidative stress and metabolic shift are a cause or consequence of hypertrophy. Spontaneously hypertensive rat (SHR) was used as the experimental model. Cardiac hypertrophy was apparent at 2 months of age, as assessed by hypertrophy index and brain natriuretic peptide gene expression. Enhanced myocardial lipid peroxidation accompanied by nuclear factor-kappa B gene expression in one-month-old SHR suggests that oxidative stress precedes the development of hypertrophy. Metabolic shift identified by reduction in the expression of peroxisome proliferator-activated receptor-alpha, medium chain acyl CoA dehydrogenase, and carnitine palmitoyltransferase 1β was seen at 4 months of age, implying that reduction of fatty acid oxidation is a consequence of hypertrophy. Information on the temporal sequence of events associated with hypertrophy will help in the prevention and reversal of cardiac remodeling. Investigations aimed at prevention of hypertrophy should address reduction of oxidative stress. Both, oxidative stress and metabolic modulation have to be considered for studies that focus on the regression of hypertrophy.

Biological evaluation of pliable hydroxyapatite-ethylene vinyl acetate co-polymer composites intended for cranioplasty

Hydroxyapatite (HAP) is undoubtedly a material suitable for repairing the defective bone tissue. However, the brittleness and non-malleability of HAP limit its clinical application as a cranioplastic analogue. To improve these properties, pliable, osteoconductive composites composed of HAP and ethylene vinyl acetate co-polymer (EVA) have been developed. This study reports the biocompatibility evaluation of the newly developed composite material. Composites of two compositions, containing 40 and 50 volume percentage of HAP, were evaluated. In vitro cell culture cytotoxity studies were carried out using L929 cell line. Intracutaneous irritation studies, and intramuscular implantation studies were carried out on rabbits. Cell culture studies showed that the composite was non-cytotoxic to mouse fibroblast cell line. Intracutaneous irritation studies did not show any gross signs of tissue reaction. Histological analysis after six months of implantation in the paravertebral muscles of rabbit showed that all the implants under study were covered with a thin soft tissue capsule. On the basis of these observations, we conclude that the composite materials are biocompatible and hence are a candidate material for implantation in the cranium.

Modulatory effect of prostaglandins on human monocyte activation for killing of high- and low-virulence strains of Paracoccidioides brasiliensis

The effect of indomethacin (Indo), a cyclo-oxygenase inhibitor, on the monocyte-mediated killing of a low- (Pb265) and a high- (Pb18) virulence strain of Paracoccidioides brasiliensis was examined. The Pb18 strain was not killed by either non-activated or interferon-gamma (IFN-gamma) -activated human monocytes but these cells did show fungicidal activity if pretreated with Indo. In contrast with IFN-gamma, tumour necrosis factor-alpha (TNF-alpha) was very effective at stimulating the fungicidal activity of monocytes. While the low-virulence strain, Pb265, could not be killed by monocytes, cells preincubated with IFN-gamma demonstrated fungicidal activity. The killing of this strain was also induced by pretreatment of monocytes with Indo. The results suggest a negative role for prostaglandins, which are synthesized via the cyclo-oxygenase pathway, in the regulation of monocyte-mediated killing of virulent and avirulent strains of P. brasiliensis and that TNF-alpha generation during the fungus-monocyte interaction is more important in the killing of Pb265 than Pb18.

[Metabolic and cardiorespiratory responses to maximal and submaximal exercise in eutrophic and stunted girls]

OBJECTIVE

The metabolic and cardiovascular responses of eutrophic girls and girls who underwent early undernutrition, were examined during physical exercise, in order to verify whether previous undernutrition could, in addition to cause a deficit in the children's height, and limit their functional capability to perform a maximal and submaximal exercise in an ergometric bicycle.

SUBJECTS

Our sample was composed of 24 girls, of which 12 were eutrophic, with 9.13 +/- 0.79 years (mean +/- s.d.), 27.64 +/- 3.64 kg of body weight, and 131.31 +/- 6.04 cm in height. The 12 early undernourished girls were 9.75 +/- 1.1 years old, 25.16 +/- 2.33 kg, and 125.06 +/- 3.9 cm high.

MEASUREMENTS

The method included clinical evaluation and ergo-spirometric test on an ergometric bicycle, from which all the metabolic and cardiac-respiratory variables were obtained and analyzed. The test protocol was an initial two minutes period with 25 watts, followed by increments of 15 watts every two minutes, until exhaustion.

RESULTS

Analysis of the results of the test of maximal effort did not reveal significant differences between eutrophic (E) and early undernourished (UN) girls in any of the variables: VO2max expressed in l/min (E = 1.11 +/- 0.25; UN = 1.02 +/- 0.19); VO2max expressed in ml/min/kg (E = 40.23 +/- 6.98; UN = 40.53 +/- 6.32), VEmax (E = 40.61 +/- 8.79; UN = 38.25 +/- 8.95), R (E = 1.13 +/- 0.07; UN = 1.13 +/- 0.05), HRmax (E = 195.33 +/- 9.13; UN = 193.85 +/- 11.18), previous % HRmax (E = 92.87 +/- 4.33; UN = 92.80 +/- 4.87), and maximum watts (E = 90.00 +/- 20.56; UN = 91.25 +/- 11.33). Analysis of the results obtained in test of submaximal effort, reflected by the intensity of effort in the anaerobic threshold (AT), showed differences between the groups in the following variables: VO2max expressed in l/min. (E = 0.77 +/- 0.14; UN = 0.62 +/- 0.13), % of VO2max (E = 70.07 +/- 7.52; UN = 61.21 +/- 9.83), HR (E = 166.58 +/- 14.25; UN = 146.33 +/- 17.40), % HRmax (E = 85.31 +/-6.41; UN = 75.50 +/- 7.73), VE (E = 24.18 +/- 5.81; UN = 17.69 +/- 4.30), % VEmax (E = 59.64 +/- 8.45; UN = 46.95 +/- 10.59). No differences were found for VO2max, expressed in l/min/kg (E = 28.06 +/- 4.87; UN = 24.81 +/- 5.31) and watts (E = 51.25 +/- 17.47; UN = 45.00 +/- 9.77).

CONCLUSION

The reestablishment of the ratio weight/height in early undernourished girls is also useful to indicate lack of limitation of functional capability to perform physical exercises.

Effect of aerobic training on ventilatory muscle endurance of spinal cord injured men

The functional consequences of ventilatory muscle impairment of spinal cord injured (SCI) subjects has been evaluated through spirometric and maximal respiratory pressure tests. Nevertheless, underlying functional abnormalities may be evident only under dynamic conditions, such as with a ventilatory muscle endurance test (VME). In order to evaluate the VME of thoracic SCI men and the effect of physical training on it we evaluated 12 SCI subjects (Group I) and 12 able-bodied controls (Group II). The subjects were submitted to clinical evaluation, spirometry, maximum voluntary ventilation in 12 s (MVV-12 sec) and a test of VME-the highest time of sustained ventilation at 70% of the maximum voluntary ventilation in isocapnic conditions (MVV-70% time). Gr. II was evaluated before and after an arm cranking aerobic training program (30 min/session, three times/week, 6 weeks) with training target heart rate corresponding to ventilatory anaerobic threshold. On the initial evaluation, Gr. I subjects presented a significantly reduced forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1) and MVV-12 sec when compared to controls (P < 0.05). Also, the VME was severely reduced in Group I (median, ranges; 1.15, 0.61-12.22) when compared to Group II (14.60, 1.20-15.00) - P < 0.001. When Gr. I subjects were separated by the level of lesion, the VME was lower in high injured (T1-T7) than intermediate (T8-T10) and low injured patients (T11-T12)-P < 0.05. After aerobic training, Group I subjects incremented significantly the FVC (P < 0.05) and the VME (P < 0.001), so that MVV-70% time values post-training were not different from the initial values of the Gr. II. In conclusion, (i) the VME of thoracic SCI men was severely reduced when compared to able-bodied controls; (ii) a 6-weeks arm cranking aerobic training program was efficient to normalize the VME of SCI subjects.

The occurrence of phthalic acid esters in various samples of commercially available sodium chloride injections (Indian Pharmacopoeia)

Conclusive evidence for the presence of di(2-ethylhexyl) phthalate (DEHP) in 15 out of 17 commercially available sodium chloride injection (Indian Pharmacopoeia) samples was obtained and concentration levels as high as 11.0 mg/500 ml of saline were detected. The presence of such contaminants in i.v. fluids, avoidable by the institution of appropriate quality control measures before manufacturing and marketing, is a matter of serious concern. Stipulated specifications in different pharmacopoeias are meant only to ensure sterility and pyrogenicity, and it is advisable that cognisance be taken of the presence of toxic contaminants e.g. di(2-ethylhexyl) phthalate.